Water scarcity is a defining issue in the United Arab Emirates (UAE), a country with limited freshwater resources and growing demand due to rapid urbanization, industrialization, and population growth. While the UAE has made remarkable strides in water management, particularly through seawater desalination, brackish water presents both an opportunity and a set of complex challenges for large-scale use.
This blog explores what brackish water is, its unique characteristics, the issues surrounding its large-scale application in the UAE, and the role of desalination of brackish water in overcoming water stress.
What is Brackish Water?
Brackish water is water that has a salinity level between freshwater and seawater. Typically, brackish water salinity ranges from 1,000 to 10,000 parts per million (ppm) of dissolved salts. It is commonly found in estuaries, coastal aquifers, and inland groundwater sources affected by salt intrusion or evaporation.
In the context of the UAE, brackish water is often extracted from underground aquifers and used for limited purposes such as irrigation, industrial processes, and—in some cases—drinking water after treatment. It offers an alternative to costly seawater desalination, but it is not without its own set of obstacles.
Why Brackish Water Matters in the United Arab Emirates?
The UAE has over 200 billion cubic meters of brackish groundwater, much of it stored in deep aquifers. Given the country’s limited surface water and unpredictable rainfall, this resource holds potential as a supplementary water supply.
Using brackish water can help:
- Reduce dependence on seawater desalination
- Support agriculture in arid zones
- Supply water to inland regions far from coastal desalination plants
However, tapping into this presents a number of technical, economic, and environmental challenges.
Challenges of Using Brackish Water on a Large Scale
1. High and Variable Salinity
Unlike seawater, which has a consistent salinity (~35,000 ppm), brackish water salinity varies significantly based on location and depth. This inconsistency complicates treatment processes and requires more advanced filtration technologies.
2. Desalination of Brackish Water is Still Costly
Although desalination of brackish water requires less energy than seawater, it still involves expensive technologies such as reverse osmosis (RO), nanofiltration, or electrodialysis. The cost can rise quickly when scaling up to supply cities or large farms.
3. Brine Disposal Issues
One of the biggest problems with brackish water desalination is brine management. The concentrated salty by-product must be disposed of safely. In inland areas of the UAE, where brine cannot be discharged into the sea, disposal becomes logistically difficult and environmentally risky.
4. Aquifer Depletion and Contamination
Over-extraction of brackish groundwater can lead to aquifer depletion and saltwater intrusion, further increasing salinity and reducing the long-term viability of the resource. Without sustainable withdrawal practices, the reliance on brackish water can backfire.
5. Scaling and Fouling in Equipment
The mineral composition of brackish water can lead to scaling and membrane fouling in desalination systems, requiring frequent maintenance and shortening equipment lifespan.
Technological Approaches and Innovations
Despite the challenges, advancements in water treatment technologies are making desalination of brackish water more feasible in the UAE:
- Energy-efficient RO membranes: New-generation membranes reduce energy consumption while maintaining high recovery rates.
- Hybrid systems: Combining solar energy with reverse osmosis helps reduce operational costs in off-grid or inland areas.
- Zero Liquid Discharge (ZLD) systems: These systems recover nearly all water from the input stream, minimizing brine waste.
The UAE’s research institutions and water authorities are actively exploring such innovations to integrate brackish water more effectively into the national water portfolio.
Sustainable Solutions for Managing Brackish Water
- Integrated Water Resource Management (IWRM)
Adopting a comprehensive approach that balances groundwater use with conservation, surface water management, and desalination will be key. - Monitoring and Regulation
Regular monitoring of aquifer health, salinity levels, and extraction rates can help prevent overuse and contamination. - Reuse and Blending Strategies
Treated brackish water can be blended with other water sources to optimize quality for specific uses, such as irrigation or cooling. - Public-Private Partnerships
Collaborations between government agencies and private companies can accelerate the deployment of cost-effective and sustainable brackish water desalination plants.
Ion Exchange’s Innovative Range of MEMBRANE SOLUTIONS
Ion Exchange offers a diverse range of products and solutions for water treatment, including:
- Reverse Osmosis: Reverse osmosis (RO) is a technique that converts seawater into freshwater by forcing it through specialized membranes using unique filters. These membranes keep the salt out. RO is easy to expand for more water, and can use less power if we add energy-saving systems. But it’s important to clean the seawater first, so the filters work well. With energy-saving systems, we can use 30 to 40 percent less power. Therefore, reverse osmosis (RO) is an effective method for obtaining fresh water from seawater.
- Electrodialysis: Electrodialysis is a technology that employs specialized membranes and electricity to separate salts from seawater, serving purposes beyond producing drinking water. This process can also be utilized to produce salt, desalinate soy sauce, and recover valuable substances from saline wastewater. Therefore, its applications extend well beyond just drinking water, encompassing various other beneficial uses.
Conclusion
While brackish water offers a promising supplement to meet the UAE’s growing water demand, its large-scale use is fraught with technical and environmental challenges. From managing brackish water salinity to solving brine disposal and ensuring aquifer sustainability, careful planning and innovation are essential.
By investing in advanced technologies and integrated water management strategies, the UAE can harness this resource more efficiently, contributing to long-term water security.